Drug marketing 101: The FDA approves drugs for specific ailments. Drug companies may not market the drug to treat any other type of ailment. If they do, it’s called off-label marketing and it is illegal.
Drug marketing 201: It’s often very profitable to engage in off-label marketing, because the fines you pay are less than the money you make doing it:
Now, I don’t know for sure that off-label marketing netted Allergan more than $600 million dollars. But, I do know that Allergan made several billion dollars selling Botox over the last few years. $600 million is definitely a large fine, but it’s only effective if it is more money than they made by promoting it off-label.
An analogy I often use: If you only had to give back half of the money you got from robbing a bank, how many banks would you rob?